Crawler vehicles have been heretofore provided with various forms of steering controls. However, crawler vehicles have opposite side crawler tracks thereof each conventionally provided with independently operable clutch and brake mechanisms whereby the individual crawler tracks may be selectively clutched and/or braked. Thus, most forms of crawler vehicles include at least four steering controls which must be operated independently or in various combinations in unison to properly control the steering thereof.
Inasmuch as most crawler tracked vehicles include other equipment supported therefrom, such as a scrapper blade, or the like, which also include manually operable controls therefor, even though the operator of a crawler tracked vehicle may use both feet and both hands in steering the vehicle and controlling various auxiliary equipment carried thereby, full steering control and operation of the auxiliary equipment of the vehicle supported therefrom, in many cases, cannot be constantly effected by the operator. Further, the actuation of as many as four different controls, independently or in combinations thereof, merely to control steerage of the crawler tracked vehicle distracts from the ability of even an experienced operator to continuously monitor and actuate the controls of auxiliary equipment carried by the crawler tracked vehicle.
Accordingly, a need exists for a control for crawler tracked vehicle for steerage thereof and which will be readily operable to achieve all steering functions with minimum effort on the part of the operator of the vehicle. Specifically, a need exists for a single oscillatable control operable through the utilization of either both hands or only one hand of the operator of the vehicle to control all steering functions of the vehicle, thereby leaving both feet and at least one hand of the operator of the vehicle free to operate various controls of auxiliary equipment which may be carried by the vehicle.
Various forms of tracked vehicles and controls including some of the general structural and operational features of the instant invention are disclosed in U.S. Pat. Nos. 980,636, 1,425,753, 1,428,688, 2,704,131, 3,862,668, 3,894,719, 3,917,014 and 3,988,893.